The present invention relates to a system for anchoring traction elements of a flexible tubular structure to an opening in a rigid wall, with the anchoring being achieved by pressing axially on a shoulder or flange after passage through an opening provided in the rigid wall. In this text, to simplify the disclosure of the invention, the term "sleeve" will be used to define the flexible annular structure and the term "bead" will define the end of the sleeve which has a larger diameter than that of the sleeve and which abuts the rigid wall, hereinafter called a "mating flange."
Sleeve with a flexible bead are known wherein the bead generally has an internal armature, i.e. embedded in the rubber, of annular form, composed of high-modulus rubber, a textile ply, a textile or metal strand, or a flexible spring. This type of reinforcement is adopted to render the bead deformable to permit mounting mating flanges after manufacture of the sleeve, by forcing the bead through the bore. The major drawback of these systems is the requirement of pinching of the flat flange between two planes, according to the device adopted, for example, by the Societe Kleber Industrie for its Dilatoflex NT expansion sleeves (technical dossier 79-BA1), or by the use of a form, obtained by maching, for a rigid part to abut a diameter inside this deformable bead, as for example in the air suspension diaphragms described in the French Pat. No. 2,127,561, or in the expansion sleeves described in French patents FR No. 2 280 852, FR No. 2 033 789 or FR No. 2 006 730.
These sleeve systems with flexible beads thus require mounting techniques which often cause a strong stress concentration at the end of the mating flange, which can go as far as damaging or even destroying the sealing function. Hence, the usual sleeves with flexible beads can only be used for moderate service pressures. To overcome these drawbacks, solutions of rigid sleeves with large contact areas with the flange have been proposed in, for example U.S. Pat. No. 2,998,986. This is in fact the solution adopted by Kleber Industrie for its built-in pipe flanges, the Endflex system described in the performer AD10 pipe catalog, page 4 or in its Dilatoflex K expansion sleeves described in catalog FC175-18, June 1984.
All these devices have high rigidity and are usually built with metal elements. Because of their design, rubber is compressed over a large contact surface area which improves stress distribution and reduces creep sensitivity, thus providing a better guarantee of tightness and the possibility of utilization at high service pressures.
However, due to their rigidity, these beads have the drawback of making it impossible to mount one-piece mating flanges after manufacture of the sleeve. Hence it is necessary to mount said mating flanges during production and to vulcanize the sleeve thus equipped with these metal parts, which considerably augments the weight and volume.
In addition, mating flanges are no longer demountable as shown by thus, the Stenflex and General Rubber catalogs. The sleeve manufacturer must keep a large inventory on hand so that sleeves equipped with flanges conforming to the various standardized connections are available.
A sleeve with demountable flanges is described in French Pat. No. 2447512 but the beads are rigid and have reinforcing collars separate from the sleeve. The proposed solution, which consists of surrounding the collar by a U-shaped rubber form, requires a very complex mold to be built.
As can be seen from the above analysis, a solution conforming to the state of the art which enables the requirements of anchoring quality (to withstand high service pressures or pulls), and ease of mounting on a flange or rigid shoulder to be met, is not known.
Hence, the object of the invention is to provide an anchoring device which offers the advantages of the two types of known beads without suffering their disadvantages. The anchoring is obtained by a bead having a large contact surface on the flange or shoulder, while offering flexibility allowing bending for passage of the bead through the bore.
Thus, the invention permits simpler manufacture of the sleeve by eliminating the weight and volume problems engendered by the necessity (in previously known solutions) of mounting the mating flanges during manufacture moreover and this represents an essential saving, it considerably reduces the need to maintain a large parts inventory due to the various connections since the same range of sleeves can be equipped with the various types of commercial or customized mating flanges at the time of delivery. Management and marketing of the sleeves is thus greatly facilitated and delivery times are considerably reduced.
The invention consists of a radial device for anchoring flexible tubular structures such as rubber hoses, deformable collars, expansion joints, and suspension diaphragms in an opening in a rigid wall by abutting a shoulder or flange after passing through an opening or hole in the rigid wall, characterized by the flexible tubular structure, or sleeve, having at least one bead reinforced by an armature with linked segments embedded in the rubber, composed of rigid elements made integral, by a flexible linking element of any type, to facilitate manufacture but allow the segments to move with respect to each other at the time of assembly, to allow the bead to bend so it can slide into the bore of the rigid wall without altering, after return to the plane shape, the radial rigidity which confers on the bead the necessary strength for its proper operation in service when it is compressed between the flange and the mating flange.
The essential element of the invention is comprised of the bead-reinforcing armature, with linked segments formed of a metal or plastic hoop with high rigidity composed of segments with varied geometric shapes, made integral with each other. The only purpose of the linking element is to join the individual segments of the armature together to form a kind of chain facilitating positioning of the armature in the bead at the time the sleeve is made. Because it is flexible, it plays no role in reinforcing the bead and does not prevent the formation of rubber bridges, i.e. physical and chemical links between the rubber-based mixtures located in the mold above and below the armature with linked segments.
At the time of manufacture, the armature is in a single piece, like a chain, which facilitates a handling and positioning in the mold. The armature may be positioned in the mold by placing the armature with linked segments directly in the mold itself; or, in a premanufacturing phase, by disposing the armature on a support comprising a layer of rubber-based mixture, with or without a textile base.
The length of the linking element between two individual consecutive segments of the armature is generally between 0.05 and 0.30 times a width of a segment, as a function of the desired flexibility of the bead, in order to allow the bead to bend mechanically radially when it is mounted in the connecting mating flange.
At the time the sleeve is made, the armature, with linked segments, can be placed in the bead either bare or wrapped in a ply of rubber mixture or of a fine textile material, the latter two possibilities having the advantages of protecting the carcass of the sleeve from damage when it contacts the edges of the armature with linked segments.
The segments, whether or not they adhere to one another, embedded in the rubber, after vulcanization form an armature rendering the bead rigid, due to the high compression rigidity of the "rubber bridges" cited above. However, these segments articulate with each other without damaging the reinforcing carcass of the sleeve and permit the bead to pass into the bore when said bead, which has become flexible, is bent, whereby the bead re-opens on the shoulder naturally after the mating flanges have been put in place. The bead, pinched between the connecting flange and the mating flange or the shoulder, retains a radial rigidity equivalent to that of a bead with a one-piece armature by the self-pinching effect.
The segments of the armature are preferably made of a metal such as steel, aluminum, Zamak, or any other material (reinforced or composite plastic) whose tensile modulus is greater than 1500 MPa.
The linking element is usually made of a wire or textile ply, of a wire or metal cable, of a plastic strand or fiber, of an elastic bracelet, or of a strip or disk of adhesive material.
The number of segments of which the armature with linked segments is composed is preferably between seven and thirteen, but it can be as large as the strength of the material and manufacturing economics permit.
The general shape of the segments is usually trapezoidal, but other possibilities may be considered such as rectangular, triangular, lozenge, or double trapezoidal shapes, cited as nonlimitative examples which shapes would complicate manufacture of the armature segments but would not interfere with their operation.